Hello, first post and don't want to start a fire but Fullish you may very well be wrong in your post. I have spent the last months reviewing the double tax agreements between Portugal/Uk/Sweden. What you are basing your "can only be taxed in one country" claim on is ONLY for the COMPANY not for the individual person or employee. For international air traffic the company that has it's seat in one country can only be taxed there, regardless of where they operate. That is at least what my crap tax lawyer and the Swedish tax authority is claiming and the double tax agreement is more or less a carbon copy between all the states involved. I would love to be proven wrong here as I am about to give away another 25% of my salary to the tax man, that is a lot of beer money!
/Scoville
Edit: Here is the link to the PDF file for UK/France:
http://www.hmrc.gov.uk/international/france.pdf
ARTICLE 8
INTERNATIONAL TRANSPORT
1. Profits derived by a
resident of a Contracting State from the operation of ships, aircraft or railway vehicles in international traffic shall be taxable only in that State.
2. Where profits within paragraph 1 are derived by a resident of a Contracting State from participation in a pool, a joint business or an international operating agency, the profits attributable to that resident shall be taxable only in the Contracting State of which he is a resident.
3. For the purposes of this Article, profits derived from the operation of ships, aircraft or railway vehicles in international traffic include:
(a) profits derived from the rental on a bareboat basis of ships, aircraft or railway vehicles; and
(b) profits derived from the use, maintenance or rental of containers;
where such rental or such use, maintenance or rental, as the case may be, is incidental to the operation of ships, aircraft or railway vehicles in international traffic.
ARTICLE 4
RESIDENCE
1. For the purposes of this Convention, the term
“resident of a Contracting State” means any person who, under the laws of that State, is liable to tax therein by reason of his domicile, residence, place of management, place of incorporation or any other criterion of a similar nature, and also includes that State and any political subdivision or local authority thereof, and any statutory body of that State, subdivision or authority.
This term does not include any person who is liable to tax in that State in respect only of income or capital gains from sources in that State.